Investigation of the effect of power ultrasound on the nucleation of water during freezing of agar gel samples in tubing vials
Investigation of the effect of power ultrasound on the nucleation of water during freezing of agar gel samples in tubing vials
复制标题
DOI：
10.1016/j.ultsonch.2011.10.009
复制
发表时间：
2012-05-01
影响因子：
8.4
通讯作者：
Zhang, Zhihang
中科院分区：
文献类型：
--
作者：
Kiani, Hossein;Sun, Da-Wen;Zhang, Zhihang
成核是冻结过程中的重要阶段，功率超声辐照可以诱导成核。在这项研究中，辐照温度的影响，（-2 ℃、-3 ℃、-4 ℃和-5 ℃）、辐照持续时间（0 s、1 s、3 s、5 s、10 s或15 s）和超声强度研究了（0.07W cm（-2）、0.14W cm（-2）、0.25 W cm（-2）、0.35W cm（-2）和0.42W cm（-2））对琼脂凝胶样品中冰的动态成核的影响。将样品放入管形小瓶后，在超声浴系统中的乙二醇-水混合物（-20 ℃）中冷冻。结果表明，如果选择最佳的超声强度和持续时间，超声照射能够在不同的过冷温度（-5 ° C至-2 ° C）下在琼脂凝胶中引发成核。评价0.25W cm（-2）超声强度和不同超声作用时间对琼脂凝胶的影响表明，1 s不足以诱导成核，3 s诱导反复成核，但较长的辐照时间导致生热，因此推迟成核。超声波强度的影响的调查表明，较高的强度的超声波是有效的，当使用较短的照射时间，而较低的强度只会导致成核时，较长的照射时间被施加。除此之外，由于超声波的加热效应在样品中产生的热量，较高的强度在较长的照射时间下无效。总之，使用超声波作为一种手段来控制结晶过程提供了有前途的应用在固体食品的冷冻，但应选择最佳条件。(C)2011 Elsevier B. V.保留所有权利。
Nucleation, as an important stage of freezing process, can be induced by the irradiation of power ultrasound. In this study, the effect of irradiation temperature (-2 degrees C, -3 degrees C, -4 degrees C and -5 degrees C), irradiation duration (0 s, 1 s,3 s,5 s, 10 s or 15 s) and ultrasound intensity (0.07W cm(-2), 0.14W cm(-2), 0.25 W cm(-2), 0.35W cm(-2) and 0.42W cm(-2)) on the dynamic nucleation of ice in agar gel samples was studied. The samples were frozen in an ethylene glycol-water mixture (-20 degrees C) in an ultrasonic bath system after putting them into tubing vials. Results indicated that ultrasound irradiation is able to initiate nucleation at different supercooled temperatures (from -5 degrees C to -2 degrees C) in agar gel if optimum intensity and duration of ultrasound were chosen. Evaluation of the effect of 0.25W cm(-2) ultrasound intensity and different durations of ultrasound application on agar gels showed that 1 s was not long enough to induce nucleation, 3 s induced the nucleation repeatedly but longer irradiation durations resulted in the generation of heat and therefore nucleation was postponed. Investigation of the effect of ultrasound intensity revealed that higher intensities of ultrasound were effective when a shorter period of irradiation was used, while lower intensities only resulted in nucleation when a longer irradiation time was applied. In addition to this, higher intensities were not effective at longer irradiation times due to the heat generated in the samples by the heating effect of ultrasound. In conclusion, the use of ultrasound as a means to control the crystallization process offers promising application in freezing of solid foods, however, optimum conditions should be selected. (C) 2011 Elsevier B.V. All rights reserved.